Sewing machine



April 21, 1936. Q R HA'A 2,037,722

SEWING MACHINE Filed Feb. 13, 1934 2 Sheets-Sheet 1 0. R. HAAS SEWING MACHINE April 21, 1936.

Filed Feb. 13, 1934 2 Sheets-Sheet 2 Ewen tor MA. AIM

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5r @TM y Vl i'iness 11 40 Patented Apr. 21, 1936 U'NirEo STATES" 2,037,722 SEWING Macnmn Otto R. Haas, North Beverly, Mask, assignor to United Shoe Machinery Corporation, Paterson,

N. J., a'corporation of hiew Jersey Application February 13, 1934, Serial No. 711,004

11 Claims; (01. '112-22'0) The present invention relates to high speed cam operated machines having relatively heavy operating parts such as are employed in, lockstitch outsole shoe sewing machines or the like.

Machines for sewing leather shoe soles and other thick tough materials are heavily .constructed to withstand strains set up by the resistance of the operating devices engaging said materials. Due to the mass of the moving parts in such machines, particularly-where rotating cams are employed, the usual parctice is-to provide some power actuated mechanisms for auto-- matically bringing the'parts to rest within as short a time as possible at the end of a seam. As

the speed of operation in such machines increases, setting the main shaft on which the cams are mounted in rotation and bringing the cam shaft to rest consume a rapidly increasing proportion of the total time required to complete a given seam. In order to benefit from the increased speed of operation in sewing, therefore, a corresponding decrease in.the time required for starting and stopping the main cam shaft is' provide the principal motions at speeds abovethese limits and an automatic driving and stop-. ping mechanism to bring the cams to rest with the operating members free of the work. Metal cams of the ordinary type for higher speeds would require further reenforcing and as a result thecams would have still greater weight.

To insure stopping of the machine accurately in the proper position, it is, usual to equip the stopping mechanism with a positive stop which engages an abutment carried by one of the cams on the cam shaft. With heavy proportions required by increased operating speeds ina machine having metal cams, impact of engagement with the positive stop in an ordinary stop motion would be likely to produce destructive shocks.

The object of the present invention, therefore, is to provide a shoe sewing or other cam operated machine having a driving and stopping mechanism which may be operated reliably at speeds in excess of those heretofore considered cams, be-

' of material which will withstand the strains imparted through the operating parts, due to the reaction in operating on thick tough materials while at the same time permitting the cam shaft to be rotated at higher speeds and more quietly than heretofore.

With these objects in view, the present invention contemplates the provision in a heavily constructed shoe sewing or other machine having oscillating members and a driving and stopping mechanism to set the machine rapidly in motion andbring it to rest in a limited time, of one or more cams composed of a phenolic resin substance for actuating the oscillating parts. Phenolic.resin having but a fractional part of the weight of metal may be made to approach metal in strength and wearing qualities, and any decrease in strength is more than ofiset by the relatively greater extent to which this substance may yield within its elastic limit. The use of cams having ability in a high degree to yield within their elastic limit reacts to reduce destructive vibrations and impacts in the machine and. to eliminate noises of operation at high speeds, thus providing an unusually quiet running and easily stopped machine.

The several features of the invention will be clearly understood from the following description and accompanying drawings, in which:-

Figure 1 is a view, in rear elevation and partly in section, of a portion of the sewing machine embodying the present invention; and Figure 2 is a side sectional view of the machine, taken on the line 2-2 of Figure 1.

The machine illustrated in the drawings is a lockstitch outsole shoe sewing machine of substantially the same construction and mode of operation as that illustrated and described in U. S.

Patent No. 1,351,090 granted August 31, 1920 to Fred Ashworth, and is provided with a curved hook needle Ill, a curved awl I2, a shuttle M, a

take-up l6, and other stitch forming and work supporting devices. Difierent motions are imparted to the work supporting and stitch forming devices through the rotation of a main sewing shaft l8 on which are fixed a series of cams 20, 22', 24, and 26 formed with continuous grooves 'orslots of rectangular cross section for actuat ing followers suitably mounted on parts connected with the different operating devices of the machine. In Figure 2, a fo1lower28 is illustrated engaging a suitably shaped cam slot ll in the cam 26 for actuating the take-up It.

The machine is started in operation and brought to rest by driving and stopping mechanisms controlled by a foot treadle connecting rod 82. To-

' engagement of clutch surfaces between the pulle and the shaft l8.

Io bring the machine to rest at the proper position with the needle and awl disengaged from the work and the final stitch in the seam completed, a low speed worm wheel 36 rotatably mounted on the shaft I8 is clutched to a braking member 38 splined to the shaft to reduce the speed of rotation substantially to the stopping point within a single rotation of the shaft. The braking member is moved into and out of engagement with the worm wheel by means of an elbow lever 40 which has on one of its ends a roll to engage a cam groove 42 formed in the braking member 38. ,The elbow lever 4|] also has a recess formed in its other end which is adapted to be engaged by a vertically sliding lock bolt 44 at a predetermined point in the cycle of operations after the treadle is released.

As soon as the shaft I8 is rotated to the proper stopping position, a positive stop abutment 46 engages a, notch 48 in the periphery of the cam 26 so as to bring the cam shaft definitely to rest with the stitch forming devices free of the work in such a position that the work may readily be withdrawn. The abutment 46 is mounted on a lever 50 fulcrumed on a stud 52 on the machine frame and is moved away from the cam when the such a speed effective operation of the mecha-- nism can only be obtained when all of the operating parts are substantially free from wear and in perfect adjustment. The greatest difficulty encountered in stopping is due in a large degree to the great mass of the cams 20 to 26 which, in the patented machine, are composed of cast iron or semi-steel. These cams are proportioned to provide adequate strength in withstanding strains set up during operation by the momentum of the oscillating parts and cam followers which engage their respective cam grooves. To increase the speed at which the machine may operate requires increasing the strength of these cams. Any increase in weight of the cams caused by adding reinforcement increases the burden on the stopping mechanism which is already at the limit of its capacity. With the type of sewing machine described, it is desirable to have the machine come to rest within a limited time after the braking effort is begun, so that the machine may accurately be stopped with the seam terminating uniformly at the desired point in the work.

The cams of the machine embodying the present invention are composed of phenolic resin which is not only lighter in weight than metal, but capable of withstanding shocks produced by impacts between the cams and the followers opaoamaa erated thereby equally as well. Due to the decrease in weight of the cams, the machine may be operated at a higher speed and brought to rest without increasing the strain on the stopping mechanism. The cams may also be increased in strength to take care of the increased strains incident to the higher speeds without adding materially to their weight.

It is well known that phenolic resin has a greater strength under compression than under tension. For this reason it is desirable'to apply special reenforcing to the present cam to resist the tension produced between the sides of the cam slots. As illustrated, the reenforcing comprises a number of superposed layers 54 of heavy woven textile fabric such as duck or'canvas arranged in parallel relation to the radial surfaces of each cam. The phenolic resin, while in its plastic condition, is moulded around the layers in a well known manner. In order to relieve as much as possible the internal strains in the cams due to the reenforcing, the sheets of the fabric are preformed to surround the follower slots, and the cams are moulded in substantially the proper shape,except for finishing the wearing surfaces. Cams constructed in this way may be so arranged that the reinforcing material will not extend through the sides of the cam slots to engage the followers, thus providing uniform wearing surfaces for guiding the followers. To further resist tension strains, the cams may be surrounded by a light band of metal reenforcing, illustrated at 56 on the cam 26 surrounding the periphery of the cam. The positive stop 46 cooperating with the cam engages the rim 56 which not only acts to strengthen the cam slot, but also provides a metal reinforcement surrounding the notch 48 against which the positive stop abutment acts.

The bearing surfaces .between any cam and its follower differ from other bearing surfaces due to the irregular shape of the cam and the limited area of contact with the follower. In most bearings the surfaces may be separated from each other by a thin film of lubricating oil, whereas, with the irregular shapes in a cam slot, such a film cannot be uniformly maintained and is considerably less effective in keeping the parts separated. When a metal cam is employed with a metal follower, excessive loads or failure of oil supply may cause irregular shaped particles of either the follower or the cam to be torn loose and to adhere to the opposite part against which it bears. These particles produce irregularities and localized wear between the follower and the cam unless the unevennesses produced by them are carefully removed. With the use of a cam composed of phenolic resin, failure to lubricate, or excessive overloads do not cause such difilculties, and to assist further in preventing damage due to oil failure, a lubricating material such as graphite may be mixed with the plastic phenolic resin before the moulding operation without detracting from the strength of the cam.

When a threaded opening for receiving a screw is formed in phenolic resin, the strength of the connection provided is inferior to that in threaded metal. For this reason, central metal hubs 58 are employed for securing the cams to the drive shaft l8. Set screws 60 for holding the cams in place are then threaded through openings in the hubs, and the hubs, being provided with radially extending teeth 62, are moulded in the cams.

Having thus described the invention, what is claimed is:

1. A shoe sewing machine having, in combination, stitch forming devices including a curved needle and a curved awl adapted to operate on sole leather, a main drive shaft, a driving and stopping mechanism for rotating the drive shaft at high speeds and for bringing it to rest after the final stitch is completed with the needle and awl disengaged from the work, and cams composed of a phenolic condensation product on the drive shaft for actuating the stitch forming devices.

2. A shoe sewing machine having, in combination, stitch forming devices including a curved needle and a curved awl adapted to operate on sole leather, 2. main drive shaft, a driving and stopping mechanism for rotating the drive shaft at high speeds and for bringing it to rest after the final stitch is completed with the needle and awl disengaged from the work, cams composed of a phenolic condensation product on the drive shaft for actuating the stitch forming devices, and a metal part on'one of said cams against which the driving and stopping mechanism acts in bringing the machine to rest with the drive shaft in proper final position.

3. A shoe sewing machine having, in combination, stitch forming devices including a curved hook needle and a curved awl adapted to operate on sole leather, a main drive shaft, a driving and stopping mechanism for rotating the drive shaft at high speeds and for bringing it to rest after the final stitch is completed with the needle and awl disengaged from the work, a cam composed of a phenolic condensation product on the drive shaft for actuating one or more of the stitch forming devices and a metallic rim for reenforcing said cam.

4. A shoe sewing machine having, in combination, stitch forming devices including a curved needle and a curved awl adapted to operate on sole leather, a main drive shaft, a driving and stopping mechanism for rotating the drive shaft at high speeds and for bringing it to rest after the final stitch is completed with the needle and awl disengaged from the work, and cams composed of a phenolic condensation product on the drive shaft for actuating the stitch forming devices, having reinforcing sheets of fibrous material cut to substantially the proper shape before incorporating in the cams.

5. A high speed machine of the type described having, in combination, a plurality of oscillating parts, a main drive shaft for the machine, a driving and stopping mechanism for driving the drive shaft and for bringing the drive shaft to rest from the maximum speed at which the machine is designed to be operated within a limited time, metallic followers connected with the oscillating parts and cams on the drive shaft composed of a phenolic condensation product and formed with parallel sided grooves fitting the followers for actuating the oscillating parts positively in both directions.

6. A high speed machine of the type described having, in combination, a plurality of oscillating parts, a main drive shaft for the machine, a driving and stopping mechanism for rotating the drive shaft at speeds above 600 R. P. M., a positive stop in the driving and stopping mechanism, means carried by the drive shaft for engaging the positive stop to bring the drive shaft to rest from the maximum speed at which the machine is designed to operate within approximately a single rotation of the drive shaft, and grooved cams composed of a phenolic condensation product on the drive shaft for actuating all of the oscillating parts.

7. A high speed machine of the type described having, in combination, a plurality of oscillating parts, a main drive shaft for the machine, a driving and stopping mechanism for rotating the drive shaft at speeds above 600 R. P. M. and for bringing the drive shaft to rest from the maxi mum speed at which the machine is designed to be operated within approximately a single rotation of the drive shaft, and cams on the drive shaft formed of a phenolic condensation product with one or more cam grooves of varying radius for actuating the oscillating parts positively in opposite directions.

8. A high speed machine of the type described having, in combination, a plurality of oscillating parts, a main drive shaft for the machine, and means comprising a metallic cam follower and a cam on the drive shaft of non-metallic material impregnated with a lubricant for actuating the oscillating parts of the machine.

9. A high speed machine of the type described having, in combination, a plurality of oscillating parts, a main drive shaft for the machine, and means comprising a metallic cam follower and a cam on the drive shaft of phenolic resin impregnated with graphite and formed with a cam groove for actuating the cam follower positively in opposite directions.

10. A high speed machine of the type described having, in combination, a plurality of oscillating parts, a main drive shaft for the machine and a cam on the drive shaft composed of a reinforced phenolic condensation product molded substantially to the proper shape with one or more cam grooves of varying radius, for actuating the oscillating parts positively in opposite directions.

11. A high speed machine of the type described having, in combination, a plurality of oscillating parts, a main drive shaft for the machine and a cam on the drive shaft having molded therein one or more follower operating grooves, said cam being composed of a phenolic condensation product having reinforcement of superposed sheets of woven fabric out to the proper configuration to provide space for said follower operating grooves when molded into the cam.

O'I'I'O R. HAAS. 

